Opposed cylinder variable piston stroke internal combustion engine



Aug. 23, 1966 c. BARGERO 3,267,917

OPPOSED CYLINDER VARIABLE PISTON STROKE INTERNAL COMBUSTION ENGINE FiledJuly 16, 1964 2 Sheets-Sheet 1 Aug. 23, 1966 c BARGERO 3,267,917

OPPOSED CYLINDER VA RIABLE PISTON STROKE INTERNAL COMBUSTION ENGINEFiled July 16, 1964 2 Sheets-Sheet 2 Fig.4

United States Patent This invention relates to an opposed cylinderinternal combustion engine of the type in which the pistons movable inthe opposed cylinders are interconnected by a rack meshing with onetoothed wheel at least, from which the rotation of the engine outletshaft is derived.

Engines of this type are known, in which two oppositely acting one-wayclutches are interposed between the outlet shaft and said toothed wheel,a device for reversing rotation being interposed between one of saidclutches and the outlet shaft.

With the above described engine arrangement the piston stroke may bemade variable. However, this advantage is obtained at the expense ofsimplicity in construction and useful life of the engine parts, mainlyon account of use of the one-way clutches.

This invention provides an opposed cylinder engine of the typespecified, wherein the movement of the outlet shaft is derived from thetoothed wheel meshing with the rack interconnecting the opposed enginepistons, by the use of a mechanism which is simple in construction andreliable in operation.

To this end the invention provides in an engine of the type specified asecond rack meshing with the toothed wheel meshing with the said rackinterconnecting the opposed engine pistons at a region which isdiametrically opposite said toothed wheel, said second rack beingmounted for displacement in the engine crank case and being connectedwith the pin of a crank carried by the outlet shaft and connected to thelatter in a manner allowing some variation of its radius.

Further characteristic features and advantages of this invention will beclearly understood from the appended description referring by way ofexample to the accompanying drawings which show an embodiment thereof,in which:

FIGURE 1 is a cross sectional view in the longitudinal middle plane ofthe two opposed cylinders of an engine according to this invention,

FIGURE 2 is a side elevational view on an enlarged scale of certaincomponents of the engine shown in FIG- URE 1,

FIGURE 3 is a sectional view on line IIIIII of FIG- URE 2,

FIGURE 4 is a sectional view on an enlarged scale of a furtherconstructional detail of the engine according to this invention.

The engine as shown on the drawing comprises a pair of opposed cylinders1, 1' carried by the crank case 2. Pistons 3, 3' are movable within thecylinders 1, 1', respectively, and are interconnected by a rigid rod themiddle portion of which is in the form of a double rack. The lower setof teeth 4 in the rack mesh with a toothed wheel 5 fitted on a shaft 6supported by the engine crank case 2. The toothed wheel 5 meshes in turnwith the rack 7 mounted for displacement in supports 8, 9 secured to thecrank case.

A connecting rod 10 is articulated to one end of the rack 7 and has itsbig end fitted on the pin 11 of a crank carried by the outlet shaft 12.The pin 11 extends laterally from a pivot 13 mounted for displacement ina radial guide in the cylindrical bulge 14 at the end of the outletshaft 12. The top set of teeth 15 in the rack interconnecting thepistons 2 and 2, meshes with the toothed wheel 16 carried by a shaft 17extending parallel with the shaft 6 and outlet shaft 12. The toothedwheel 16 meshes with a crank 18 interconnecting two pistons 19, 19'movable in cylinders 20, 20, respectively, situated above the cylinders1, 1' of the engine and extending parallel with the latter.

The piston-cylinder unit 19, .1920, 20' acts as a scavenging pump whichsupplies air, drawn through valves or ports not shown on the drawing, tothe cylinders 1, 1 through conduits 21, 21', respectively. The outletopenings of the latter conduits within the cylinders 1, 1 is controlledby valves 22, 22, respectively, opening to the inside of the cylinders1, 1' and being normally biased to their closed position by springs 23,23' the action of springs 23, 23. A nozzle 24, FIGURE 4, is provided ineach valve and connects through a small-diameter axial bore 25 in thevalve stem 122 and through a fitting 26 for a small hose 126 with anexternal fuel supply reservoir (not shown).

The valves 22, 22' together with their stems 122 are each supported by atubular connecting pipe 121 screwed at its end into an opening in thecylinder top, its other end being screwed to a conduit 21 or 21. Whenthe valve 22 (or 22') is in its closed position as shown in FIGURE 4,the axial conduit 25 is cut off from the connecting pipe 26 by insertionof the free end of the stem 122 into a blind bore in a tumbler fixedwithin the connecting pipe 121. Connection is established only afterdisplacement of the valve 22 (or 22') against the action of the spring23 (or 23) by the air thrust from the cylinder 26 or 20' of thescavenging pump. The valves are moreover each provided in proximity totheir respective nozzle 24 with a check valve 124 preventing flow ofpressure gases from the cylinder 1 (or 1') into the conduit 25 when thelatter is cut off from the connecting pipe 26.

A spark plug 27, 27', respectively, is provided on each cylinder headand is fed with high-voltage electric current from any conventionalsystem.

In operation the engine is started by rotating the outlet shaft oreither shaft 6 or 17 when the toothed wheels 5, 16 are keyed to thelatter shafts. Supply of electric current to the spark plug on thecylinder, such as cylinder 1 in which compression of the fuel mixturefirst takes place effects ignition in the cylinder 1 and the firstworking stroke of the piston 3. Towards the end of this stroke thepiston 3 uncovers the exhaust port 28, thereby starting the exhaust andscavenging stroke on cylinder 1 by means of air flowing from thescavenging pump cylinder 20 above the cylinder 1 in which the expansionstroke has just been performed. Flow of pressure air from the scavengingpump cylinder 20 opens the valve 22 against the spring 23 andsimultaneously draws into the cylinder 1 a quantity of liquid fuelthrough the nozzle 24.

The compression stroke is in the meantime performed in cylinder 1 tillspontaneous ignition of the mixture therein, or during a shorter periodtill a lower compression ratio is reached when ignition is eifected bysupplying high-voltage current to the spark plug 27 before compressionis driven far enough to effect continuous ignition.

Variation in stroke length of the pistons 3 and '3 of the engine, hencein the stroke of the scavenging pump pistons 19, 19' is made possible bythe fact that the spacing of the crank pin 11 from the axis of theoutlet shaft 12 is variable Within given limits which are determineddependently upon the maximum admissible stroke of the pistons 3, 3,which depends upon the spacing of the heads of the two opposedcylinders.

It will be understood that details can be widely varied within theprinciple of this invention without departing from the scope thereof setforth in the appended claims.

This applies more particularly to the number of cylinders which is aneven number and may be larger than two provided further auxiliarycomponents required for transmission of power to a common outlet shaftare associated with every added cylinder pair.

What I claim is:

1. Internal combustion engine of the type having a crank case, at leastone pair of opposite coaxial cylinders, one piston slidable in eachcylinder, at first rack interconnecting said pistons, an engine outletshaft and a toothed wheel meshing with said first rack, said enginecomprising further a second rack meshing with said toothed wheel at aregion thereof which is diametrically opposed to the region at whichsaid toothed wheel meshes with the said first rack, means for supportingsaid second rack in the engine crank case and means for connecting thesaid second rack with the engine outlet shaft, the last mentioned meanscomprising a crank carried by the engine outlet shaft and radiallyfreely displa-ceable with respect to the latter, a pin on said crankparallel to said outlet shaft and a connecting rod interposed betweenone end of the said second rack and the said pin.

2. Internal combustion engine as set forth in claim 1, comprisingfurther a scavenging pump having a pair of opposed coaxial cylinderseach arranged adjacent one of the engine cylinders and being parallel tothe latter, and having also a pair of pistons each movable in one of thepump cylinders and a third rack connecting said pistons,

d the said third rack meshing With a toothed Wheel drivingly connectedwith the said first rack connecting the engine pistons.

3. Internal combustion engine as set forth in claim 2, wherein eachcylinder of the scavenging pump is arranged above one engine cylinderand wherein the said third rack meshes with a toothed Wheel meshingsimultaneously with the said first rack connecting the said enginepistons.

4. Internal combustion engine as set forth in claim 2 comprising furthera pair of conduits each connecting one of the pump cylinders with one ofthe engine cylinders, and a check valve provided at the inlet of each ofsaid conduits in one engine cylinder and elastic means for each valveurging the latter towards its closed position.

5. Internal combustion engine as set forth in claim 4, having a fuelinflow nozzle incorporated in each valve, the said nozzle beingconnected with a fuel feeding conduit, a valve being provided betweensaid nozzle and said fuel feeding conduit, the said valve opening onopening of the valve incorporating the said nozzle.

No references cited.

MARK NEWMAN, Primary Examiner.

W. E. BURNS, Assistant Examiner.

1. INTERNAL COMBUSTION ENGINE OF THE TYPE HAVING A CRANK CASE, AT LEASTONE PAIR OF OPPOSITE COAXIAL CYLINDERS, ONE PISTON SLIDABLE IN EACHCYLINDER, A FIRST RACK INTERCONNECTING SAID PISTONS, AN ENGINE OUTLETSHAFT AND A TOOTHED WHEEL MESHING WITH SAID FIRST RACK, SAID ENGINECOMPRISING FURTHER A SECOND RACK MESHING WITH SAID TOOTHED WHEEL AT AREGION THEREOF WHICH IS DIAMETRICALLY OPPOSED TO THE REGION AT WHICHSAID TOOTHED WHEEL MESHES WITH THE SAID FIRST RACK, MEANS FOR SUPPORTINGSAID SECOND RACK IN THE ENGINE CRANK CASE AND MEANS FOR CONNECTING THESAID SECOND RACK WITH THE ENGINE OUTLET SHAFT, THE LAST MENTIONED MEANSCOMPRISING A CRANK CARRIED BY THE ENGINE OUTLET SHAFT AND RADIALLYFREELY DISPLACEABLE WITH RESPECT TO THE LATTER, A PIN ON SAID CRANKPARALLEL TO SAID OUTLET SHAFT AND A CONNECTING ROD INTERPOSED BETWEENONE END OF THE SAID SECOND RACK AND THE SAID PIN.